1. Field of the Invention
The present invention relates to intermediate electrical connectors provided between two connection objects to electrically connect them.
2. Related Art
Japanese patent application Kokai No. 8-330005 discloses such an intermediate electrical connector. As FIGS. 9(A) and (B) show, a contact element 52 is attached to an insulating board 51 through an aperture 53. The contact element 52 has a circular section of metallic sheet with a diameter larger than that of the aperture 53. It is provided with a plurality of spiral grooves 52A to form a plurality of spiral contact pieces 52B. The periphery 52C of the contact element 52 is fixed to the insulating board 51 such that the spiral contact pieces 52B project from the apertures alternately in opposite directions.
In use, as shown in FIG. 9(B), the upwardly extending contact pieces 52B are brought into contact with a spherical contact section 54A of an upper connection object 54 while the downwardly extending contact pieces 52B are brought into contact with a flat contact section of a lower connection object 55, thereby electrically connecting the two connection objects 54 and 55.
However, the above device has the following disadvantages.
(1) The length of electrical path between the tips of the contact pieces is so large that the inductance and electrical resistance are considerably high. The high inductance causes crosstalk or ground bounce at high signal speeds. The high resistance causes high power consumption, producing large amounts of heat.
(2) There is no wiping effects caused by the contact pressure at the contact area between the contact element and the mating connection object. Consequently, when a film of dirt is formed on the contact surface, no automatic cleaning action is obtained upon contact, thus failing to provide a stable contact.
(3) A plurality of transmission paths are formed so that any difference in the length of the paths causes a signal delay.